Since the mid-twentieth century high-heeled footwear for women has fallen in and out of popular fashion trend several times, most notably in the 1990's, when lower heels and even flats predominated. Lower heels gave way to higher heels, and the shape of the heel itself has gone through a number of fashionable iterations. Today, high heels are typically worn with heights varying from a “kitten heel” of 1.5 inches to a “stiletto heel” of 4.0 inches or more. Extremely high-heeled shoes, such as those higher than 5.0 inches, are normally worn only for aesthetic reasons, but are not considered practical. High heels have seen significant controversy in the medical field, with many podiatrists seeing patients whose severe foot problems have been caused almost exclusively by high-heeled footwear.
While many women choose to wear high-heeled shoes for a various aesthetic reasons—such as accentuating the appearance of the calves to make the wearer's posture and gait more seductive, appearance taller, legs longer and feet smaller—there are myriad reasons that high heeled shoes should not be worn, almost exclusively related to health and practicality. For example, high heels can cause foot and tendon pain and increase the likelihood of sprains and fractures. They can make a woman's calves appear more rigid and sinewy. High heels can create foot deformities such as hammertoes and bunions and can cause lower back pain. Altered forces at the wearer's knee caused by walking in high heels may predispose a wearer to degenerative changes in the knee joint. Frequent wearing of high heels results in a higher incidence of degenerative joint disease of the knees. This is because they cause a decrease in the normal rotation of the foot, which puts more rotation stress on the knee.
High-heeled shoes slant the foot forward and downward, while bending the toes up. The more that the feet are forced into this position, the more it may cause portions of the calf muscle to shorten. This may cause problems when the wearer chooses lower heels or flat-soled shoes. When the foot slants forward, a much greater weight is transferred to the ball of the foot and the toes, thereby increasing the likelihood of damage to the underlying soft tissue that supports the foot. In many shoes, style dictates function, either compressing the toes or forcing them together, possibly resulting in blisters, corns, hammer toes, bunions, plantar fasciitis and many other medical conditions, most of which are permanent and require surgery to alleviate the pain. High heels, because they tip the foot forward, put pressure on the lower back by making the wearer's rump push outwards, crushing the lower back vertebrae and contracting the muscles of the lower back.
Despite the medical issues surrounding high-heel wear, a few podiatrists recommend well-constructed low-to-moderate heels for some patients. A slight elevation of the heel improves the angle of contact between the metatarsals and the horizontal plane, thereby more closely approximating the proper angle and resulting in proper weight distribution of a medium-to-high-arched foot. Other foot specialists, however, argue that any heel causes unnecessary stresses on the various bones and joints of the foot.
However, the popularity of high-heels for wear by women remains popular and the cost of replacing a wardrobe of high-heels with low heels is relatively prohibitive. Therefore, a method of modifying existing high-heeled shoes is needed to provide cushioning and reduce the angulation of the wearer's foot to alleviate discomfort and to maintain the wearer's foot at an angle less likely to cause medical issues.